In commonly owned U.S. Pat. No. 3,784,283 there has been disclosed a zoom objective comprising an afocal forward lens unit with variable magnification and a main lens unit of fixed focal length, the two units being separated by an intervening diaphragm space. The forward lens unit consists of an axially shiftable front component (I) of positive refractivity, an axially shiftable intermediate component (II) of negative refractivity and an axially fixed positive component (III) in the form of a single lens. Within a zoom range having a varifocal ratio of about 3:1 between the miximum overall focal length f.sub.max and the minimum overall focal length f.sub.min, the intermediate component is displaced between a limiting position near the front component at the upper end of the range (f.sub.max) and another limiting position close to the fixed positive lens (III) at the lower end of the range (f.sub.min), the distance of this movable component from the fixed positive lens of the forward unit in the latter position being considerably less than the length of the diaphragm space separating the fixed positive lens from the main lens unit (IV). At the limits of the zoom range, the distance of the front component (I) from the fixed positive lens (III) is the same.